One of the problems facing manufacturers of high performance aircraft is aerodynamic drag and the penalties in speed and fuel consumption which occur as a result of such drag. One aircraft location where drag often occurs is the interface between the airframe fairing and the moveable divergent flaps of the nozzle of a gas turbine engine. Air flowing off the airframe fairing may become turbulent, forming recirculation vortices at the interface, and increasing the overall drag of aircraft.
A solution to this problem is to provide an aerodynamic surface at the airframe fairing/movable flap interface. In the past, essentially rigid fairing flaps have been used to span between the divergent flaps and the static components of the nozzle or airframe. However, the rigid fairing flaps used in the past are unsuitable for use in conjunction with thrust vectoring gas turbine exhaust nozzles, due to the geometries involved.
In a typical aircraft having a thrust vectoring nozzle, the airframe fairing may have a curved surface and a trailing edge characterized by a complex geometry, such as chevrons. The surface of the divergent flap may likewise have a complex geometry. In addition, the nozzle's divergent flaps may rotate and translate with respect to the airframe fairing during aircraft operation. Although rigid fairing flaps attached to the trailing edge of the airframe fairing may provide an aerodynamic surface at the divergent flap position for which they were designed, rigid fairing flaps would produce substantial drag at many other divergent flap positions.